The pelvis (plural pelves or pelvises) is either the lower part of the trunk of the human body[1] between the abdomen and the thighs (sometimes also called pelvic region of the trunk) or the skeleton embedded in it[2] (sometimes also called bony pelvis, or pelvic skeleton).

The pelvic region of the trunk includes the bony pelvis, the pelvic cavity (the space enclosed by the bony pelvis), the pelvic floor, below the pelvic cavity, and the perineum, below the pelvic floor.[1] The pelvic skeleton is formed in the area of the back, by the sacrum and the coccyx and anteriorly and to the left and right sides, by a pair of hip bones.

The two hip bones connect the spine with the lower limbs. They are attached to the sacrum posteriorly, connected to each other anteriorly, and joined with the two femurs at the hip joints. The gap enclosed by the bony pelvis, called the pelvic cavity, is the section of the body underneath the abdomen and mainly consists of the reproductive organs (sex organs) and the rectum, while the pelvic floor at the base of the cavity assists in supporting the organs of the abdomen.

In mammals, the bony pelvis has a gap in the middle, significantly larger in females than in males. Their young pass through this gap when they are born.

The pelvic region of the trunk is the lower part of the trunk, between the abdomen and the thighs.[1] It includes several structures: the bony pelvis, the pelvic cavity, the pelvic floor, and the perineum. The bony pelvis (pelvic skeleton) is the part of the skeleton embedded in the pelvic region of the trunk. It is subdivided into the pelvic girdle and the pelvic spine. The pelvic girdle is composed of the appendicularhip bones (ilium, ischium, and pubis) oriented in a ring, and connects the pelvic region of the spine to the lower limbs. The pelvic spine consists of the sacrum and coccyx.[1]

the pelvic cavity, typically defined as a small part of the space enclosed by the bony pelvis, delimited by the pelvic brim above and the pelvic floor below; alternatively, the pelvic cavity is sometimes also defined as the whole space enclosed by the pelvic skeleton, subdivided into:

The pelvic skeleton is formed posteriorly (in the area of the back), by the sacrum and the coccyx and laterally and anteriorly (forward and to the sides), by a pair of hip bones.
Each hip bone consists of 3 sections, ilium, ischium, and pubis. During childhood, these sections are separate bones, joined by the triradiate cartilage. During puberty, they fuse together to form a single bone.

The pelvic floor has two inherently conflicting functions: One is to close the pelvic and abdominal cavities and bear the load of the visceral organs; the other is to control the openings of the rectum and urogenital organs that pierce the pelvic floor and make it weaker. To achieve both these tasks, the pelvic floor is composed of several overlapping sheets of muscles and connective tissues.
[5]

Modern humans are to a large extent characterized by bipedal locomotion and large brains. Because the pelvis is vital to both locomotion and childbirth, natural selection has been confronted by two conflicting demands: a wide birth canal and locomotion efficiency, a conflict referred to as the "obstetrical dilemma". The female pelvis, or gynecoid pelvis,[8] has evolved to its maximum width for childbirth—a wider pelvis would make women unable to walk. In contrast, human male pelvises are not constrained by the need to give birth and therefore are more optimized for bipedal locomotion.[9]

The principal differences between male and female true and false pelvis include:

The female pelvis is larger and broader than the male pelvis which is taller, narrower, and more compact.[10]

The female inlet is larger and oval in shape, while the male sacral promontory projects further (i.e. the male inlet is more heart-shaped).[10]

The sides of the male pelvis converge from the inlet to the outlet, whereas the sides of the female pelvis are wider apart.[11]

The angle between the inferior pubic rami is acute (70 degrees) in men, but obtuse (90–100 degrees) in women. Accordingly, the angle is called subpubic angle in men and pubic arch in women.[10] Additionally, the bones forming the angle/arch are more concave in females but straight in males.[12]

The distance between the ischia bones is small in males, making the outlet narrow, but large in females, who have a relatively large outlet. The ischial spines and tuberosities are heavier and project farther into the pelvic cavity in males. The greater sciatic notch is wider in females.[12]

The iliac crests are higher and more pronounced in males, making the male false pelvis deeper and more narrow than in females.[12]

The male sacrum is long, narrow, more straight, and has a pronounced sacral promontory. The female sacrum is shorter, wider, more curved posteriorly, and has a less pronounced promontory.[12]

The acetabula are wider apart in females than in males.[12] In males, the acetabulum faces more laterally, while it faces more anteriorly in females. Consequently, when males walk the leg can move forwards and backwards in a single plane. In females, the leg must swing forward and inward, from where the pivoting head of the femur moves the leg back in another plane. This change in the angle of the femoral head gives the female gait its characteristic (i.e. swinging of hips).[13]

Each side of the pelvis is formed as cartilage, which ossifies as three main bones which stay separate through childhood: ilium, ischium, pubis. At birth the whole of the hip joint (the acetabulum area and the top of the femur) is still made of cartilage (but there may be a small piece of bone in the great trochanter of the femur); this makes it difficult to detect congenital hip dislocation by X-raying.

"In terms of comparative anatomy the human scapula represents two bones that have become fused together; the (dorsal) scapula proper and the (ventral) coracoid. The epiphyseal line across the glenoid cavity is the line of fusion. They are the counterparts of the ilium and ischium of the pelvic girdle."

The skeleton of the pelvis is a basin-shaped ring of bones connecting the vertebral column to the femora.

Its primary functions are to bear the weight of the upper body when sitting and standing, transferring that weight from the axial skeleton to the lower appendicular skeleton when standing and walking, and providing attachments for and withstanding the forces of the powerful muscles of locomotion and posture. Compared to the shoulder girdle, the pelvic girdle is thus strong and rigid.[1]

Its secondary functions are to contain and protect the pelvic and abdominopelvic viscera (inferior parts of the urinary tracts, internal reproductive organs), providing attachment for external reproductive organs and associated muscles and membranes.[1]

The pelvic girdle consists of the two hip bones. The hip bones are connected to each other anteriorly at the pubic symphysis, and posteriorly to the sacrum at the sacroiliac joints to form the pelvic ring. The ring is very stable and allows very little mobility, a prerequisite for transmitting loads from the trunk to the lower limbs.
[16]

As a mechanical structure the pelvis may be thought of as four roughly triangular and twisted rings. Each superior ring is formed by the iliac bone; the anterior side stretches from the acetabulum up to the anterior superior iliac spine; the posterior side reaches from the top of the acetabulum to the sacroiliac joint; and the third side is formed by the palpableiliac crest. The lower ring, formed by the rami of the pubic and ischial bones, supports the acetabulum and is twisted 80-90 degrees in relation to the superior ring.
[17]

An alternative approach is to consider the pelvis part of an integrated mechanical system based on the tensegrityicosahedron as an infinite element. Such a system is able to withstand omnidirectional forces—ranging from weight-bearing to childbearing—and, as a low energy requiring system, is favoured by natural selection.
[18]

The pelvic inclination angle is the single most important element of the human body posture and is adjusted at the hips. It is also one of the rare things that can be measured at the assessment of the posture. A simple method of measurement was described by the British orthopedist Philip Willes and is performed by using an inclinometer.

The lumbosacral joint, between the sacrum and the last lumbar vertebra, has, like all vertebal joints, an intervertebral disc, anterior and posterior ligaments, ligamenta flava, interspinous and supraspinous ligaments, and synovial joints between the articular processes of the two bones. In addition to these ligaments the joint is strengthened by the iliolumbar and lateral lumbosacral ligaments. The iliolumbar ligament passes between the tip of the transverse process of the fifth lumbar vertebra and the posterior part of the iliac crest. The lateral lumbosacral ligament, partly continuous with the iliolumbar ligament, passes down from the lower border of the transverse process of the fifth vertebra to the ala of the sacrum. The movements possible in the lumbosacral joint are flexion and extension, a small amount of lateral flexion (from 7 degrees in childhood to 1 degree in adults), but no axial rotation. Between ages 2–13 the joint is responsible for as much as 75% (about 18 degrees) of flexion and extension in the lumbar spine. From age 35 the ligaments considerably limit the range of motions.
[19]

The three extracapsular ligaments of the hip joint—the iliofemoral, ischiofemoral, and pubofemoral ligaments—form a twisting mechanism encircling the neck of the femur. When sitting, with the hip joint flexed, these ligaments become lax permitting a high degree of mobility in the joint. When standing, with the hip joint extended, the ligaments get twisted around the femoral neck, pushing the head of the femur firmly into the Acetabulum, thus stabilizing the joint.
[20] The zona orbicularis assists in maintaining the contact in the joint by acting like a buttonhole on the femoral head.[21] The intracapsular ligament, the ligamentum teres, transmits blood vessels that nourish the femoral head.[22]

The inferior parts of latissimus dorsi, one of the muscles of the upper limb, arises from the posterior third of the iliac crest.[26] Its action on the shoulder joint are internal rotation, adduction, and retroversion. It also contributes to respiration (i.e. coughing).[27] When the arm is adducted, latissimus dorsi can pull it backward and medially until the back of the hand covers the buttocks.[26]

In a longitudinal osteofibrous canal on either side of the spine there is a group of muscles called the erector spinae which is subdivided into a lateral superficial and a medial deep tract. In the lateral tract, the iliocostalis lumborum and longissimus thoracis originates on the back of the sacrum and the posterior part of the iliac crest. Contracting these muscles bilaterally extends the spine and unilaterally contraction bends the spine to the same side. The medial tract has a "straight" (interspinales, intertransversarii, and spinalis) and an "oblique" (multifidus and semispinalis) component, both of which stretch between vertebral processes; the former acts similar to the muscles of the lateral tract, while the latter function unilaterally as spine extensors and bilaterally as spine rotators. In the medial tract, the multifidi originates on the sacrum.
[28]

The muscles of the abdominal wall are subdivided into a superficial and a deep group.

The superficial group is subdivided into a lateral and a medial group. In the medial superficial group, on both sides of the centre of the abdominal wall (the linea alba), the rectus abdominis stretches from the cartilages of ribs V-VII and the sternum down to the pubic crest. At the lower end of the rectus abdominis, the pyramidalis tenses the linea alba. The lateral superficial muscles, the transversus and external and internal oblique muscles, originate on the rib cage and on the pelvis (iliac crest and inguinal ligament) and are attached to the anterior and posterior layers of the sheath of the rectus.
[29]

Flexing the trunk (bending forward) is essentially a movement of the rectus muscles, while lateral flexion (bending sideways) is achieved by contracting the obliques together with the quadratus lumborum and intrinsic back muscles. Lateral rotation (rotating either the trunk or the pelvis sideways) is achieved by contracting the internal oblique on one side and the external oblique on the other. The transversus' main function is to produce abdominal pressure in order to constrict the abdominal cavity and pull the diaphragm upward.
[29]

There are two muscles in the deep or posterior group. Quadratus lumborum arises from the posterior part of the iliac crest and extends to the rib XII and lumbar vertebrae I-IV. It unilaterally bends the trunk to the side and bilaterally pulls the 12th rib down and assists in expiration. The iliopsoas consists of psoas major (and occasionally psoas minor) and iliacus, muscles with separate origins but a common insertion on the lesser trochanter of the femur. Of these, only iliacus is attached to the pelvis (the iliac fossa). However, psoas passes through the pelvis and because it acts on two joints, it is topographically classified as a posterior abdominal muscle but functionally as a hip muscle. Iliopsoas flexes and externally rotates the hip joints, while unilateral contraction bends the trunk laterally and bilateral contraction raises the trunk from the supine position.
[30]

The posterior group includes the gluteii maximus, medius, and minimus. Maximus has a wide origin stretching from the posterior part of the iliac crest and along the sacrum and coccyx, and has two separate insertions: a proximal which radiates into the iliotibial tract and a distal which inserts into the gluteal tuberosity on the posterior side of the femoral shaft. It is primarily an extensor and lateral rotator of the hip joint, but, because of its bipartite insertion, it can both adduct and abduct the hip. Medius and minimus arise on the external surface of the ilium and are both inserted into the greater trochanter. Their anterior fibers are medial rotators and flexors while the posterior fibers are lateral rotators and extensors. The piriformis has its origin on the ventral side of the sacrum and is inserted on the greater trochanter. It abducts and laterally rotates the hip in the upright posture and assists in extension of the thigh.
[31] The tensor fasciae latae arises on the anterior superior iliac spine and inserts into the iliotibial tract.[33] It presses the head of the femur into the acetabulum and flexes, medially rotates, and abducts the hip.[31]

The ventral hip muscles are important in the control of the body's balance. The internal and external obturator muscles together with the quadratus femoris are lateral rotators of the hip. Together they are stronger than the medial rotators and therefore the feet point outward in the normal position to achieve a better support. The obturators have their origins on either sides of the obturator foramen and are inserted into the trochanteric fossa on the femur. Quadratus arises on the ischial tuberosity and is inserted into the intertrochanteric crest. The superior and inferior gemelli, arising from the ischial spine and ischial tuberosity respectively, can be thought of as marginal heads of the obturator internus, and their main function is to assist this muscle.
[31]

Anterior and posterior thigh muscles

The muscles of the thigh can be subdivided into adductors (medial group), extensors (anterior group), and flexors (posterior group). The extensors and flexors act on the knee joint, while the adductors mainly act on the hip joint.

The anterior thigh muscles form the quadriceps which is inserted on the patella with a common tendon. Three of the four muscles have their origins on the femur, while rectus femoris arises from the anterior inferior iliac spine and is thus the only of the four acting on two joints.[35]

In later stages of pregnancy the fetus's head aligns inside the pelvis.[37] Also joints of bones soften due to the effect of pregnancy hormones.[38] These factors may cause pelvic joint pain (symphysis pubis dysfunction or SPD).[39][40] As the end of pregnancy approaches, the ligaments of the sacroiliac joint loosen, letting the pelvis outlet widen somewhat; this is easily noticeable in the cow.

Hip fractures often affect the elderly and occur more often in females, and this is frequently due to osteoporosis. There are also different types of pelvic fracture often resulting from traffic accidents.

There are many anatomical variations of the pelvis. In the female the pelvis can be of a much larger size than normal, known as a giant pelvis or pelvis justo major, or it can be much smaller, known as a reduced pelvis or pelvis justo minor.[42] Other variations include an android pelvis the normal shape of the male pelvis, in women this shape can prove problematic in childbirth.

Throughout the 20th century pelvimetric measurements were made on pregnant women to determine whether a natural birth would be possible, a practice today limited to cases where a specific problem is suspected or following a caesarean delivery. William Edgar Caldwell and Howard Carmen Moloy studied collections of skeletal pelves and thousands of stereoscopic radiograms and finally recognized three types of female pelves plus the masculine type. In 1933 and 1934 they published their typology, including the Greek names since then frequently quoted in various handbooks: Gynaecoid (gyne, woman), anthropoid (anthropos, human being), platypelloid (platys, flat), and android (aner, man).
[43][44]

The gynaecoid pelvis is the so-called normal female pelvis. Its inlet is either slightly oval, with a greater transverse diameter, or round. The interior walls are straight, the subpubic arch wide, the sacrum shows an average to backward inclination, and the greater sciatic notch is well rounded. Because this type is spacious and well proportioned there is little or no difficulty in the birth process. Caldwell and his co-workers found gynaecoid pelves in about 50 per cent of specimens.

The platypelloid pelvis has a transversally wide, flattened shape, is wide anteriorly, greater sciatic notches of male type, and has a short sacrum that curves inwards reducing the diameters of the lower pelvis. This is similar to the rachitic pelvis where the softened bones widen laterally because of the weight from the upper body resulting in a reduced anteroposterior diameter. Giving birth with this type of pelvis is associated with problems, such as transverse arrest. Less than 3 per cent of women have this pelvis type.

The android pelvis is a female pelvis with masculine features, including a wedge or heart shaped inlet caused by a prominent sacrum and a triangular anterior segment. The reduced pelvis outlet often causes problems during child birth. In 1939 Caldwell found this type in one third of white women and in one sixth of non-white women.

The anthropoid pelvis is characterized by an oval shape with a greater anteroposterior diameter. It has straight walls, a small subpubic arch, and large sacrosciatic notches. The sciatic spines are placed widely apart and the sacrum is usually straight resulting in deep non-obstructed pelvis. Caldwell found this type in one quarter of white women and almost half of non-white women.

However, Caldwell and Moloy then complicated this simple fourfold scheme by dividing the pelvic inlet into posterior and anterior segments. They named a pelvis according to the anterior segment and affixed another type according to the character of the posterior segment (i.e. anthropoid-android) and ended up with no less than 14 morphologies. Notwithstanding the popularity of this simple classification, the pelvis is much more complicated than this as the pelvis can have different dimensions at various levels of the birth canal.[46]

Caldwell and Moloy also classified the physique of women according to their types of pelves: the gynaecoid type has small shoulders, a small waist and wide hips; the android type looks square-shaped from behind; and the anthropoid type has wide shoulders and narrow hips.[47] Lastly, in their article they described all non-gynaecoid or "mixed" types of pelves as "abnormal", a word which has stuck in the medical world even though at least 50 per cent of women have these "abnormal" pelves.[48]

The classification of Caldwell and Moloy was influenced by earlier classifications attempting to define the ideal female pelvis, treating any deviations from this ideal as dysfunctions and the cause of obstructed labour. In the 19th century anthropologists and others saw an evolutionary scheme in these pelvic typologies, a scheme since then refuted by archaeology. Since the 1950s malnutrition is thought to be one of the chief factors affecting pelvic shape in the Third World even though there are at least some genetic component to variation in pelvic morphology.[49]

Nowadays obstetric suitability of the female pelvis is assessed by ultrasound. The dimensions of the head of the fetus and of the birth canal are accurately measured and compared, and the feasibility of labor can be predicted.

The pelvic girdle was present in early vertebrates, and can be tracked back to the paired fins of fish that were some of the earliest chordates.[50]

The shape of the pelvis, most notably the orientation of the iliac crests and shape and depth of the acetabula, reflects the style of locomotion and body mass of an animal. In bipedal mammals, the iliac crests are parallel to the vertically oriented sacroiliac joints, where in quadrupedal mammals they are parallel to the horizontally oriented sacroiliac joints. In heavy mammals, especially in quadrupeds, the pelvis tend to be more vertically oriented because this allows the pelvis to support greater weight without dislocating the sacroiliac joints or adding torsion to the vertebral column.

In ambulatory mammals the acetabula are shallow and open to allow a wider range of hip movements, including significant abduction, than in cursorial mammals. The lengths of the ilium and ischium and their angles relative to the acetabulum are functionally important as they determine the moment arms for the hip extensor muscles that provide momentum during locomotion.[51]

In addition to this, the relatively wide shape (front to back) of the pelvis provides greater leverage for the gluteus medius and minimus. These muscles are responsible for hip abduction which plays an integral role in upright balance.

In primates, the pelvis consists of four parts - the left and the right hip bones which meet in the mid-line ventrally and are fixed to the sacrum dorsally and the coccyx. Each hip bone consists of three components, the ilium, the ischium, and the pubis, and at the time of sexual maturity these bones become fused together, though there is never any movement between them. In humans, the ventral joint of the pubic bones is closed.

The present-day morphology of the pelvis is inherited from the pelvis of our quadrupedal ancestors. The most striking feature of evolution of the pelvis in primates is the widening and the shortening of the blade called the ilium. Because of the stresses involved in bipedal locomotion, the muscles of the thigh move the thigh forward and backward, providing the power for bi-pedal and quadrupedal locomotion.[53]

The drying of the environment of East Africa in the period since the creation of the Red Sea and the African Rift Valley saw open woodlands replace the previous closed canopy forest. The apes in this environment were compelled to travel from one clump of trees to another across open country. This led to a number of complementary changes to the human pelvis. It is suggested that bipedalism was the result.

1.
Anatomical terms of bone
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Many anatomical terms descriptive of bone are defined in anatomical terminology, and are often derived from Greek and Latin. A long bone is one that is cylindrical in shape, being longer than it is wide, however, the term describes the shape of a bone, not its size which is relative. Long bones are found in the arms and legs, as well as in the fingers, long bones function as levers, they move when muscles contract. They are responsible for the bodys height. A short bone is one that is cube-like in shape, being equal in length, width. The only short bones in the skeleton are in the carpals of the wrists. Short bones provide stability and support as well as some limited motion, the term “flat bone” is something of a misnomer because, although a flat bone is typically thin, it is also often curved. Examples include the bones, the scapulae, the sternum. Flat bones serve as points of attachment for muscles and often protect internal organs, flat bones do not have a medullary cavity because they are thin. An irregular bone is one that not have an easily classified shape. These bones tend to have complex shapes, like the vertebrae that support the spinal cord. Many facial bones, particularly the ones containing sinuses, are classified as irregular bones, a sesamoid bone is a small, round bone that, as the name suggests, is shaped like a sesame seed. These bones form in tendons where a deal of pressure is generated in a joint. The sesamoid bones protect tendons by helping them overcome compressive forces, sesamoid bones vary in number and placement from person to person but are typically found in tendons associated with the feet, hands, and knees. The only type of bone that is common to everybody is the kneecap which is also the largest of the sesamoid bones. A condyle (/ˈkɒndəl/ or /ˈkɒndaɪl/, is the prominence at the end of a bone. The epicondyle refers to a projection near a condyle, particularly the medial epicondyle of the humerus, an eminence refers to a relatively small projection or bump, particularly of bone, such as the medial eminence. A process refers to a large projection or prominent bump. Both tubercle and tuberosity refer to a projection or bump with a roughened surface and these terms are derived from Tuber, originally from the Latin swelling A ramus refers to an extension of bone, such as the ramus of the mandible in the jaw or Superior pubic ramus

2.
X-ray
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X-radiation is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz, X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. Spelling of X-ray in the English language includes the variants x-ray, xray, X-rays with high photon energies are called hard X-rays, while those with lower energy are called soft X-rays. Due to their ability, hard X-rays are widely used to image the inside of objects, e. g. in medical radiography. The term X-ray is metonymically used to refer to an image produced using this method. Since the wavelengths of hard X-rays are similar to the size of atoms they are useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air, the length of 600 eV X-rays in water is less than 1 micrometer. There is no consensus for a definition distinguishing between X-rays and gamma rays, one common practice is to distinguish between the two types of radiation based on their source, X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus. This definition has problems, other processes also can generate these high-energy photons. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m and this criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. Occasionally, one term or the other is used in specific contexts due to precedent, based on measurement technique. Thus, gamma-rays generated for medical and industrial uses, for radiotherapy, in the ranges of 6–20 MeV. X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds and this makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a period of time causes radiation sickness. In medical imaging this increased risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy, hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects, the most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry and research

3.
Abdomen
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The abdomen constitutes the part of the body between the thorax and pelvis, in humans and in other vertebrates. The region occupied by the abdomen is termed the abdominal cavity, in arthropods it is the posterior tagma of the body, it follows the thorax or cephalothorax. The abdomen stretches from the thorax at the diaphragm to the pelvis at the pelvic brim. The pelvic brim stretches from the joint to the pubic symphysis and is the edge of the pelvic inlet. The space above this inlet and under the thoracic diaphragm is termed the abdominal cavity, the boundary of the abdominal cavity is the abdominal wall in the front and the peritoneal surface at the rear. The abdomen contains most of the organs of the digestive tract. Hollow abdominal organs include the stomach, the intestine. Organs such as the liver, its attached gallbladder, and the function in close association with the digestive tract. The spleen, kidneys, and adrenal glands also lie within the abdomen, along with blood vessels including the aorta. Anatomists may consider the urinary bladder, uterus, fallopian tubes, finally, the abdomen contains an extensive membrane called the peritoneum. A fold of peritoneum may completely cover certain organs, whereas it may only one side of organs that usually lie closer to the abdominal wall. Anatomists call the type of organs retroperitoneal. For example, the stomach of ruminants is divided into four chambers – rumen, in vertebrates, the abdomen is a large cavity enclosed by the abdominal muscles, ventrally and laterally, and by the vertebral column dorsally. Lower ribs can also enclose ventral and lateral walls, the abdominal cavity is upper part of the pelvic cavity. It is attached to the cavity by the diaphragm. Structures such as the aorta, inferior vena cava and esophagus pass through the diaphragm, both the abdominal and pelvic cavities are lined by a serous membrane known as the parietal peritoneum. This membrane is continuous with the visceral peritoneum lining the organs, the abdomen in vertebrates contains a number of organs belonging, for instance, to the digestive tract and urinary system. There are three layers of the abdominal wall and they are, from the outside to the inside, external oblique, internal oblique, and transverse abdominal

4.
Pelvic cavity
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The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet and its lower boundary is the pelvic floor. The pelvic cavity primarily contains reproductive organs, the bladder, the pelvic colon. The rectum is placed at the back of the pelvis, in the curve of the sacrum and coccyx, in the female, the uterus and vagina occupy the interval between these viscera. The pelvic cavity also contains major arteries, veins, muscles, the pelvis has an anteroinferior, a posterior, and two lateral pelvic walls, and an inferior pelvic wall, also called the pelvic floor. The parietal peritoneum is attached here and to the abdominal wall, the lesser pelvis is the space enclosed by the pelvic girdle and below the pelvic brim, between the pelvic inlet and the pelvic floor. This cavity is a short, curved canal, deeper on its posterior than on its anterior wall, some consider this region to be the entirety of the pelvic cavity. Others define the pelvic cavity as the space including the greater pelvis. The lesser pelvis contains the pelvic colon, rectum, bladder, the rectum is at the back, in the curve of the sacrum and coccyx, the bladder is in front, behind the pubic symphysis. In the female, the uterus and vagina occupy the interval between these viscera, the pelvic splanchnic nerves arising at S2-S4 are in the lesser pelvis. The greater pelvis is the space enclosed by the pelvic girdle above and it is generally considered part of the abdominal cavity. Some consider this part of the pelvic cavity, while others reframe the classification question by calling the combination the abdominopelvic cavity. The greater pelvis supports the intestines, and transmits part of their weight to the wall of the abdomen. The femoral nerve from L2-L4 is in the pelvis

5.
Hip bone
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The hip bone is a large flat bone, constricted in the center and expanded above and below. In some vertebrates it is composed of three parts, the ilium, ischium, and the pubis, the two hip bones join at the pubic symphysis and together with the sacrum and coccyx comprise the skeletal component of the pelvis – the pelvic girdle which surrounds the pelvic cavity. They are connected to the sacrum, which is part of the axial skeleton, each hip bone is connected to the corresponding femur through the large ball and socket joint of the hip. The hip bone is formed by three parts, ilium, ischium, and pubis, at birth, these three components are separated by hyaline cartilage. They join each other in a Y-shaped portion of cartilage in the acetabulum, by the end of puberty the three regions will have fused together, and by the age of 25 they will have ossified. The two hip bones join each other at the pubic symphysis, together with the sacrum and coccyx, the hip bones form the pelvis. Ilium is the uppermost and largest region and it makes up two fifths of the acetabulum. The body of ilium forms the joint with the sacrum. The edge of the wing of ilium forms the S-shaped iliac crest which is located through the skin. The iliac crest shows clear marks of the attachment of the three abdominal wall muscles, the ischium forms the lower and back part of the hip bone and is located below the ilium and behind the pubis. The ischium is the strongest of the three regions that form the hip bone and it is divisible into three portions, the body, the superior ramus, and the inferior ramus. The body forms approximately one-third of the acetabulum, the ischium forms a large swelling, the tuberosity of the ischium, also referred to colloqially as the sit bone. When sitting, the weight is placed upon the ischial tuberosity. The gluteus maximus covers it in the posture, but leaves it free in the seated position. The pubic region or pubis is the ventral and anterior of the three forming the hip bone. It is divisible into a body, a superior ramus, the body forms one-fifth of the acetabulum. The body forms the wide, strong, medial and flat portion of the bone which unites with the other pubic bone in the pubic symphysis. The fibrocartilaginous pad which lies between the surfaces of the coxal bones, that secures the pubic symphysis, is called the interpubic disc

6.
Perineum
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In human anatomy, the perineum is the region of the body between the pubic symphysis and the coccyx, including the perineal /pɛrəˈniːəl/ body and surrounding structures. There is some variability in how the boundaries are defined, the perianal area is a subset of the perineal area. The perineum is a zone for both males and females. Perineal tears and episiotomy often occur in childbirth with first-time deliveries, the perineum is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. The perineum is below the diaphragm and between the legs. It is an area that includes the anus and, in females. Its definition varies, it can refer to only the structures in this region. The perineum corresponds to the outlet of the pelvis and it is found in both males and females. In males, it is found between the bulb of penis and the anus, in females, is found between the vagina and anus, and about 1.25 cm in front of the latter. The perineal body is essential for the integrity of the pelvic floor, at this point, the following muscles converge and are attached,1. Anterior fibers of the levator ani 5, fibers from male or female external urinary sphincter 6. Deep transverse perineal muscle The terminology of the fascia can be confusing. This stems from the fact there are two parts to the fascia, the superficial and deep parts, and each of these can be subdivided into superficial. The following areas are classified as parts of the perineal region, Perineal pouches, superficial. It is bounded laterally by obturator internus muscle, medially by pelvic diaphragm, anal canal Pudendal canal – contains internal pudendal artery and the pudendal nerve. Extensive deformations of the floor structures occur in the course of a vaginal delivery. Approximately 85% of women suffer some extent of perineal trauma during a vaginal delivery, obstetric perineal trauma is a distressing event significantly contributing to postpartum morbidity and frustration of women after delivery. In many women the childbirth trauma is manifested in advanced age when the mechanisms of the pelvic floor become weakened making the problem more serious among the aged population

7.
Offspring
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In biology, offspring are the young born of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a general way. This can refer to a set of offspring, such as the chicks hatched from one clutch of eggs, or to all the offspring. Human offspring are referred to as children, male children are sons, offspring can occur after mating or after artificial insemination. Offspring contains many parts and properties that are precise and accurate in what they consist of, and what they define. As the offspring of a new species, also known as a child or f1 generation, consist of genes of the father and the mother, each of these offspring contains numerous genes which have coding for specific tasks and properties. Males and females contribute equally to the genotypes of their offspring, in which gametes fuse and form. An important aspect of the formation of the parent offspring is the chromosome, depending on which genes are dominantly expressed in the gene will result in the sex of the offspring. The female will give an X chromosome, whereas the male, depending on the situation. If a male offspring is produced, the gene will consist of an X, if two X chromosomes are expressed and produced, it produces a female offspring. Cloning is the production of an offspring which represents the identical genes as its parent, reproductive cloning begins with the removal of the nucleus from an egg, which holds the genetic material. In order to clone an organ, a cell is to be produced. A common misconception of cloning is that it produces a copy of the parent being cloned. Cloning copies the DNA/genes of the parent and then creates a genetic duplicate, the clone will not be a similar copy as he or she will grow up in different surroundings from the clone and may encounter different opportunities and experiences. Although mostly positive, cloning also faces some setbacks in terms of ethics, though cell division and DNA replication is a vital part of survival, there are many steps involved and mutations can occur with permanent change in an organisms and their offsprings DNA. Lineal descendant kinship and descent Clutch size Infanticide Litter Parent-offspring conflict Parental investment

8.
Thigh
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In humans, the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb, the single bone in the thigh is called the femur. This bone is thick and strong, and forms a ball and socket joint at the hip. The femur is the bone in the thigh and serves for an attachment site for all muscles in the thigh. The head of the femur articulates with the acetabulum in the bone forming the hip joint, while the distal part of the femur articulates with the tibia. By most measures the femur is the strongest bone in the body, the femur is also the longest bone in the body. The femur is categorised as a bone and comprises a diaphysis. In cross-section, the thigh is divided up three separate compartments, divided by fascia, each containing muscles. These compartments use the femur as an axis, and are separated by connective tissue membranes. Each of these compartments has its own blood and nerve supply, posterior compartment muscles of the thigh are the hamstring muscles, which include semimembranosus, semitendinosus, and biceps femoris. Medial compartment muscles are adductor magnus, adductor longus and adductor brevis, because the major muscles of the thigh are the largest muscles of the body, resistance exercises of them stimulate blood flow more than any other localized activity. The arterial supply is by the artery and the obturator artery. The lymphatic drainage closely follows the arterial supply and drains to the lumbar lymphatic trunks on the corresponding side, which in turn drains to the cisterna chyli. The deep venous system of the consists of the femoral vein, the proximal part of the popliteal vein, and various smaller vessels. The venae perfortantes connect the deep and the system, which consists of the saphenous veins. Thigh weakness can result in a positive Gowers sign on physical examination

9.
Pelvic floor
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The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, the pelvic floor separates the pelvic cavity above from the perineal region below. The right and left levator ani lie almost horizontally in the floor of the pelvis, separated by a gap that transmits the urethra, vagina. The levator ani is usually considered in three parts, pubococcygeus, puborectalis, and iliococcygeus, the pubococcygeus, the main part of the levator, runs backward from the body of the pubis toward the coccyx and may be damaged during parturition. Some fibers are inserted into the prostate, urethra, and vagina, the right and left puborectalis unite behind the anorectal junction to form a muscular sling. Some regard them as a part of the sphincter ani externus, the iliococcygeus, the most posterior part of the levator ani, is often poorly developed. The coccygeus, situated behind the levator ani and frequently tendinous as much as muscular, extends from the spine to the lateral margin of the sacrum. The pelvic cavity of the pelvis has the pelvic floor as its inferior border. The perineum has the floor as its superior border. However, other include the fascia as part of the diaphragm. In practice, the two terms are used interchangeably. Posteriorly, the pelvic floor extends into the anal triangle, the pelvic floor has two hiatuses, Anteriorly urogenital hiatus through which urethra and vagina pass through and posteriorly rectal hiatus through which anal canal passes. It is important in providing support for pelvic viscera, e. g. the bladder, intestines, the uterus and it facilitates birth by resisting the descent of the presenting part, causing the fetus to rotate forwards to navigate through the pelvic girdle. It helps maintain optimal intra-abdominal pressure, in women, the levator muscles or their supplying nerves can be damaged in pregnancy or childbirth. There is some evidence that these muscles may also be damaged during a hysterectomy, pelvic surgery using the perineal approach is an established cause of damage to the pelvic floor. In female high-level athletes, perineal trauma is rare and is associated with sports, water-skiing, bicycle racing. Damage to the pelvic floor not only contributes to urinary incontinence, pelvic organ prolapse occurs in women when pelvic organs protrude into or outside of the vagina. The causes of pelvic organ prolapse are not unlike those that contribute to urinary incontinence

Taking an X-ray image with early Crookes tube apparatus, late 1800s. The Crookes tube is visible in center. The standing man is viewing his hand with a fluoroscope screen. The seated man is taking a radiograph of his hand by placing it on a photographic plate. No precautions against radiation exposure are taken; its hazards were not known at the time.

1896 plaque published in "Nouvelle Iconographie de la Salpetrière", a medical journal. In the left a hand deformity, in the right same hand seen using radiography. The authors designated the technique as Röntgen photography.